Android Support (#166)

1. Add vpnservice tauri plugin for android.
2. add workflow for android.
3. Easytier Core support android, allow set tun fd.

tauri-plugin-vpnservice/ios/Tests/PluginTests/PluginTests.swift

@@ -0,0 +1,8 @@
+import XCTest
+@testable import ExamplePlugin
+
+final class ExamplePluginTests: XCTestCase {
+    func testExample() throws {
+        let plugin = ExamplePlugin()
+    }
+}